1. Field of the Invention
This invention relates to new pyrimidine compounds, including derivatives of 2,4,5,6-tetra-aminopyrimidine, and salts thereof, and to their use as developer component in oxidation hair-dyeing preparations.
So-called oxidation hair-dye preparations play a prominent part in the dyeing of hair by virtue of their intensive colors and good fastness properties. Hair-dyeing preparations of this type contain oxidation dye precursors in a cosmetic carrier. Developer substances and coupler substances are used as oxidation dye precursors. Under the effect of oxidizing agents or atmospheric oxygen, the developer components from the actual dyes either in conjunction with one another or through coupling with one or more coupler components.
A certain developer substance is also capable of forming very different shades by combination with different couplers. In spite of this, it is often not possible to achieve the variety of natural hair colors with one and the same developer substance. In practice, therefore, it is generally necessary to combine various developer components and coupler components to obtain a single, natural-looking hair color.
Good oxidation dye precursors have to satisfy above all the following requirements. Thus, they have to form the required shades with sufficient intensity and fastness during the oxidative coupling reaction. In addition, they must be readily absorbed by human hair with no significant differences between mismanaged hair and freshly washed hair. They are required to be stable to light, heat and the effect of chemical reducing agents, for example permanent wave lotions. Finally, they should not overly stain the scalp and, above all, should be safe to use from the toxicological and dermatological viewpoint.
The developer substances normally used are primary aromatic amines containing another free or substituted hydroxy or amino group in the para position or ortho position, also diaminopyridine derivatives, heterocyclic hydrazone derivatives and 4-aminopyrazolone derivatives. The so-called couplers used include m-phenylenediamine derivatives, naphthols, resorcinol derivatives and pyrazolones.
The use of 2,4,5,6-tetra-aminopyrimidines as a developer component in hair dyeing preparations was known from U.S. Re. No. 30,199. The 2,4,5,6-tetra-aminopyrimidine derivatives described therein give only a limited range of shades with a number of couplers, primarily among the yellows, browns and reds.
The present invention relates to new 2,4,5,6-tetra-aminopyrimidine derivatives corresponding to the following formula ##STR3## in which R.sup.1 is a group of the formula --NH--(CH.sub.2).sub.n --NH--, where n=2-4, a group of the formula --NH--CH.sub.2 --CH(OH)--CH.sub.2 --NH-- or a group of the formula ##STR4## R.sup.2 and R.sup.3, which may be the same or different, independently of one another represent hydrogen, chlorine or a group of the formula --OR.sup.4, where R.sup.4 is a C.sub.1 -C.sub.4 alkyl group, and A is a CH group or a nitrogen atom, and to the salts thereof.
These new 2,4,5,6-tetra-aminopyrimidine derivatives corresponding to formula I are oxidation dye precursors of the developer substance type, i.e. they are capable of forming dyes under the effect of oxidizing agents. In the presence of coupler substances, however, particularly bright and intense colors are formed. Suitable coupler substances are, above all, the m-phenylenediamines, m-aminophenols, resorcinols, 1-naphthol, 1,5- and 2,6-dihydroxynaphthalene, hydroxy and aminopyridines, hydroxy-quinolines and aminopyrazolones. With these and other known coupler substances, the 2,4,5,6-tetra-aminopyrimidine derivatives according to the invention form a wide range of colors extending from orange-yellow to deep blue. Above all, however, colors which would otherwise only be obtainable using two or more different developers can be produced with many couplers. Accordingly, the 2,4,5,6-tetra-aminopyrimidine derivatives of formula I according to the invention are eminently suitable for use as oxidation dye precursors of the developer type in hair dyeing preparations. Hair dyeing preparations containing the 2,4,5,6-tetra-aminopyrimidine derivatives according to the invention, as the developer component in addition to standard coupler components, show particularly uniform absorption both on mismanaged hair and on freshly washed hair. The dye finishes obtained show high stability to heat. Preference is attributed, particularly by virtue of their ready availability to the 2,4,5,6-tetra-aminopyrimidine derivatives of formula I in which R.sup.2 and R.sup.3 are hydrogen where A is a nitrogen atom and in which at least one of the groups R.sup.2 and R.sup.3 is hydrogen where A is a CH group. By virtue of their high molecular weight, the new 2,4,5,6-tetra-aminopyrimidine derivatives are substantially nonresorbable which favorably affects their toxicological and dermatological properties.
The 2,4,5,6-tetra-aminopyrimidine derivatives of formula I according to the invention may be prepared by reacting under reflux conditions compounds corresponding to the following formula ##STR5## with a 2-alkylmercapto-4,6-diamino-5-nitrosopyrimidine in which the alkyl group contains 1-4 carbon atoms, such as 2-methylmercapto-4,6-diamino-5-nitrosopyrimidine, and catalytically hydrogenating the compounds obtained (intermediate stage) corresponding to the following formula ##STR6## In formulae II and III, R.sup.1, R.sup.2, R.sup.3 and A have the same meanings as in formula I.
In the catalytic hydrogenation, the usual catalysts are employed using nickel (Raney nickel) platinum or palladium on a support or carrier, preferably platinum or palladium on carbon, with hydrogen under pressure.
The 2,4,5,6-tetra-aminopyrimidine derivatives according to the invention may be isolated and used in hair dyeing preparations either as such or in the form of their salts with inorganic or organic acids, for example as hydrochlorides, sulfates, phosphates, acetates, propionates, lactates or citrates.
The present invention also relates to hair dyeing preparations containing oxidation dye precursors in a cosmetic carrier which contain as oxidation dye precursors 2,4,5,6-tetra-aminopyrimidine derivatives of formula I as developer component in a quantity of from 0.05 to 10 millimoles per 100 g of hair dye preparation in addition to standard coupler components and, optionally, substantive hair dyes.
In the hair dyes according to the invention, the developer substances and the coupler substances are generally used in equimolar quantities, although a certain excess of individual oxidation dye precursors is not a disadvantage, so that developer substances and coupler substances may be used in a molar ratio of from 1:0.5 to 1:2, more desirably from 1:0.75 to 1:1.25. With a slight excess of the coupler compound, the hair dyeing preparations according to the invention form slightly more intense colors. There is no need for the 2,4,5,6-tetra-aminopyrimidine derivatives corresponding to formula I to be used as individual compounds. Instead, mixtures of these compounds may also be used.
To modify the hair color, known substantive hair dyes, for example nitrophenylenediamine derivatives, anthraquinone dyes or indophenols, may also be added to the hair dyeing preparations according to the invention.
To produce the hair dyeing preparations according to the invention, the oxidation dye precursors and, optionally, substantive dyes are incorporated in a suitable cosmetic carrier. Carriers such as these are, for example, creams, emulsions, gels or even surfactant-containing foaming solutions, for example shampoos, or other preparations which are suitable for application to the hair. Standard constituents of cosmetic preparations, such as these are, for example, wetting agents and emulsifiers, such as anionic, nonionic or ampholytic surfactants, for example fatty alcohol sulfates, alkane sulfonates, .alpha.-olefin sulfonates, fatty alcohol polyglycol ether sulfates, ethylene oxide adducts with fatty alcohols, fatty acids and alkylphenols, sorbitan fatty acid esters and fatty acid partial glycerides, and fatty acid alkanolamides. Also thickeners are included such as, for example, methyl or hydroxyethyl cellulose, starch, fatty alcohols, paraffin oils, fatty acids. Also often added are perfume oils and hair-care additives such as, for example, water-soluble cationic polymers, protein derivatives, pantothenic acid and cholesterol.
The constituents of the cosmetic carriers are used in the usual quantities for producing the hair dyeing preparations according to the invention. For example, emulsifiers are used in concentrations of from 0.5 to 30%, usually about 5-20%, by weight and thickeners in concentrations of from 0.1 to 25%, usually about 1-10%, by weight, based on the preparations as a whole. The oxidation dye precursors are incorporated in the carrier in quantities of from 0.2 to 5% by weight and preferably in quantities of from 1 to 3% by weight, based on the preparation as a whole.
In principle, the dye may be oxidatively developed with air. However, it is preferred to use a chemical oxidizing agent, particularly when, in addition to dyeing, the hair is also to be lighted. Suitable oxidizing agents are, in particular, hydrogen peroxide or adducts thereof with urea, melamine or sodium borate and also mixtures of these hydrogen peroxide adducts with potassium peroxydisulfate.
The hair dyeing preparations according to the invention may be used in a mildly acidic, neutral or alkaline medium, irrespective of the cosmetic carrier used, for example a cream, gel or shampoo. The hair dyeing preparations are preferably used in the pH range from 8 to 10. They may be used at temperatures of from 15.degree. C. to 40.degree. C.
After a contact time of about 30 minutes, the hair dyeing preparation is removed by rinsing from the hair to be dyed. The hair is then washed with a mild shampoo and dried. Washing with a shampoo is unnecessary when a carrier of high surfactant content, for example a dye shampoo, is used.
The following Examples are intended to illustrate the invention without limiting it in any way.